MITSUBISHI MICROCOMPUTERS
M37754M8C-XXXGP, M37754M8C-XXXHP
M37754S4CGP, M37754S4CHP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
As shown in Figure 13, there are three different interrupt priority de-
Table 4. Value set in processor interrupt level (IPL) during an interrupt
tection time from which one is selected by software. After the se-
lected time has elapsed, the highest priority is determined and is
processed after the currently executing instruction has been com-
pleted.
Interrupt types
Setting value
Reset
0
____
DBC
7
Watchdog timer
Zero divide
7
The time is selected with bits 4 and 5 of the processor mode register
0 (address 5E16) shown in Figure 14. Table 5 shows the relationship
between these bits and the number of cycles. After a reset, the pro-
cessor mode register 0 is initialized to “0016.” Therefore, the longest
time is automatically set, however, the shortest time must be se-
lected by software.
Not change value of IPL.
Not change value of IPL.
BRK instruction
Table 5. Relationship between interrupt priority detection time select
bit and number of cycles
Priority detection time select bit
Number of cycles
Bit 5
Bit 4
0
0
1
0
1
0
7 cycles of φBIU
4 cycles of φBIU
2 cycles of φBIU
φBIU
Operation code fetch cycle
Sampling pulse
Priority detection time
0
1
2
Select one from 0 to 2 with
bits 4 and 5 of processor
mode register 0
Fig. 13 Interrupt priority detection time
20
RENESAS [ RENESAS TECHNOLOGY CORP ]
